A power supply grid can comprise power supply networks with different voltage levels such as a high-voltage transmission grid and lower voltage distribution grids to which a plurality of energy resources can be connected. These energy resources include, among other types, power supply consumers or loads which consume electrical power. The loads can for instance be formed by electrical machines or devices in factories or private households. The power consumed by the loads is generated by a second type of energy resource, namely power sources or power generation units which can be connected to the high-voltage transmission grid and/or to the lower voltage distribution grid. Conventional power generation units comprise power plants such as coal power plants or nuclear power plants connected to the high-voltage transmission grid. In power supply grids, there is a trend that more renewable power sources are employed to generate electrical power. These renewable power sources or power generation units comprise for instance wind farms with a plurality of wind generators as well as photovoltaic generation units installed on roofs or solar power farms with a plurality of photovoltaic entities generating electrical power from sunlight. These renewable power sources forming energy resources of the power supply grid are distributed and volatile and significant numbers are connected to the lower voltage distribution grid of the power supply grid. With the increasing portion of electrical power generated by renewable power sources, it becomes more difficult to guarantee a stability of the power supply grid and to provide always sufficient capacities. As a consequence, distributed energy storage devices are used and connected to the power supply grid. Accordingly, a power supply grid comprises as energy resources electrical loads or consumers consuming electrical power and drawing electrical power from the power supply grid as well as power sources which are adapted to feed electrical power into the power grid and a third type, namely electrical energy storage devices which are adapted to store electrical power. The cost of a storage device increases with the maximum storage capacity of the device. Accordingly, storage devices must be employed in order to use their storage capacity efficiently. Distributed electrical storage devices can be used efficiently by combining multiple usages comprising local energy buffering, local blackout prevention of a blackout of the power supply grid as well as efficient support of the power supply grid, in particular with respect to grid stability and capacity. The fourth type of energy resource is formed by any combination of the first three types.
An energy resource such as an energy storage device is controlled by an energy resource controller. This energy resource controller is connected via a communication infrastructure or communication network to a distributed or central control unit. This communication infrastructure can be a public communication infrastructure such as a public communication network. Since the communication link between the energy resource controller and the control unit via a communication network can be unreliable, there can be times when no or only limited communication between the energy resource controller and the control unit via the communication link is possible. If the communication link between the control unit and the energy resource controller of the energy resource is lost or the bandwidth of the communication link is strongly limited, a control of the distributed energy resource by the remote control unit is no longer possible.
In a conventional energy management system an affected energy resource whose energy resource controller has lost its communication link to the control unit cannot make any further contribution to the power supply grid. Further, during times where a communication is established but a bandwidth of the communication link is low due to other services on the same communication link, the energy resource cannot be any longer controlled to make a contribution to the power supply grid.
Accordingly, there is a need to provide an apparatus and a method for performing an energy management in a power supply grid which allows that an affected energy resource whose communication link has been lost or limited can still make a contribution to the operation of the power supply grid, preferably in combination with other usages.